Any concerns at the White House about a potentially divisive Democratic primary seemed put to rest when Vice President Joe Biden took himself out of the running last fall.

But with the first votes being cast in a week in Iowa and an eye toward preserving his own legacy, President Obama came off the sidelines Monday and inserted himself into the increasingly bitter nomination fight between his former secretary of State, Hillary Clinton, and the populist insurgent, Sen. Bernie Sanders (I-Vt.).

Obama abandoned almost all pretense of disengagement by suggesting in an interview that Clinton is a “good, smart, tough” person up against a “bright, shiny” new alternative who remains less tested than her, a reminder about picking a nominee who can win a tough general election.

“She can govern and she can start here, Day One, more experienced than any non-vice-president has ever been who aspires to this office,” he told Politico.

Obama stopped far short of expressing an endorsement or even a preference. Still, his willingness to step personally into 2016 politics reveals how deeply he believes Clinton is the candidate best suited to build on his achievements, even as the White House has had to scramble to maintain a veneer of detachment in the surprisingly competitive primary fight.

“I heard Clinton might pick you for vice president,” said Jose Pulido, who represents workers at a hog slaughterhouse...

(Kate Linthicum)

Obama’s public comments reflect a long-held belief in his world that Clinton would carry on the work he started. Early last year, a flow of administration aides headed from Washington to Brooklyn, home to Clinton’s campaign headquarters. And four members of Obama’s Cabinet and two former members have endorsed her.

The White House has insisted Obama would remain neutral during the Democratic primary, though he has signaled he won’t be a bystander in 2016, most notably in his State of the Union address.

The speech came a week after Obama made an initial, inadvertent foray into the race. In an op-ed in the New York Times as he promoted his new executive actions to limit gun violence, Obama wrote that he wouldn’t support any candidate who didn’t agree with him on “common-sense” solutions to the issue -- listing firearms manufacturers’ “virtual immunity” from lawsuits, codified into law a decade ago, as an example of the industry’s outsized influence in Washington.

It was precisely an issue Clinton had been hitting Sanders on for weeks. A White House official said the administration had not anticipated the way in which the essay would play in the primary until the Clinton campaign drew attention to it.

After facing repeated questions about the issue, White House Press Secretary Josh Earnest told reporters that the White House welcomed Sanders' statement that he would support undoing the 2006 law that he had supported, and rejected questions about whether he and others at the White House were trying to help Clinton.

“I spent the last 90 seconds saying good things about Sen. Sanders’ commitment to common-sense gun laws, so I have a feeling I’m more likely to hear from my friends in the Clinton campaign than my friends in the Sanders campaign right now,” Earnest said at one point.

Obama aides don’t deny that Clinton campaign officials have quick access to their White House counterparts, given how many are former colleagues. But both sides insist no messages or agendas are coordinated in a way that would influence the primary campaign. John Podesta, the Clinton campaign national chairman and a former senior White House advisor, said that in the case of the op-ed, for instance, they only read it when it was first posted online.

“If we are going to do something that we think they need a heads-up on, if you will, Jennifer [Palmieri] or I’ll call up our former colleagues and let them know we are going to do it,” said Podesta, referring to himself and Palmieri, the former White House communications director who now holds the same role for Clinton. “But we don’t consult on our policy positions. I don’t think that would be appropriate and probably they don’t think that would be appropriate.”

Lots of Democrats are happy to see the spirited primary back-and-forth. It's nothing but good for the party as a whole and the eventual nominee, in their view.

“No way” is there a downside to the Clinton-Sanders match, said Donna Brazile, the longtime Democratic strategist who led then-Vice President Al Gore's campaign in a similar primary fight against liberal outsider Bill Bradley.

“We can use a dose of passion and an ounce of fever to get voters ready to participate,” she said.

As the first contests near and the polls tighten, Clinton has only seemed to draw herself closer to the president. Campaigning in Iowa on Sunday at a Baptist church, for instance, Clinton spoke at length about how she and the president forged a close bond after a difficult campaign against each other in 2008.

“And I am so grateful for this opportunity that I now have to run, to be your president, to build on the progress that he has accomplished because that's really what's at stake,” she said.

Clinton has met with Obama at the White House multiple times since leaving the State Department, most recently in December for an informal lunch. The White House insists that Sanders has also had at least one-on-one meeting with Obama, though aides have not identified the date or circumstances of that encounter. The time Sanders appears on the White House’s public visitor logs for a private meeting was in December 2014, before he launched his campaign.

Sanders campaign officials say they interact with the White House on occasion. They also note that Sanders met privately with Biden in recent months but don’t expect the president to take a position in the race.

“He’d be very comfortable supporting Bernie Sanders,” spokesman Tad Devine said. “If Bernie is successful and becomes the nominee, I see President Obama, the vice president as well, as being two of the leaders who can help to pull the party together behind them.”